The Hamburglar first appeared in McDonald's advertising in 1971.
The character was introduced as a mischievous figure associated with hamburgers and became part of the McDonaldland cast. His early design was darker and more villain-like than the later version familiar to many audiences. McDonald's subsequently redesigned him with a smaller, childlike appearance and a more playful personality.
The Hamburglar is often dated incorrectly because Ronald McDonald appeared earlier, in the 1960s, and the characters were used together in later campaigns. His role was primarily branding and entertainment rather than a description of a real product or restaurant practice. The character helped make McDonald's advertising recognizable to children.